Since October 28, 2011 we have been operating a gas control system for the 
nuclear reactor at Unit 2 of Fukushima Daiichi Nuclear Power Station. On 
November 1, as a result of the nuclide analysis by collecting charcoal 
filters installed inside a dust radiation monitor, some radioactive Xe135 
was detected, a nuclide with a short half-life (around 9 hours).

Today we have submitted a report to Nuclear and Industrial Safety Agency of 
the Ministry of Economy, Trade and Industry.

<Appendices> 
 Detection of Xe135 at Unit 2 of Fukushima Daiichi Nuclear Power Station 
                                                               (PDF 299KB)